Traditionally, registration of continuous form material with a cutter blade is known to be an operator intensive process that requires constant overview and supervision in order to prevent cut line drift due to slippage of the material, which may cause loss of sheet registration and synchronization. In order to avoid slippage of the continuous form material during registration, cutter feeders have been known to use tractor feed pin holes formed on an edge of continuous form or sheet material in order to index feed the continuous form material to cutter blades of cutters. For example, where a tractor feeder is configured with a pin assembly, individual pins of the pin assembly may project through tractor feed pin holes formed on an edge of the continuous form material. A shaft may be configured to drive the pin assembly and thereby advance the continuous form material a predetermined number of pin holes to move the continuous form material one sheet length to position the lead edge of each successive form up to a cutter blade position. In order to ensure there is no slippage, a cover assembly may be positioned over the pin assembly in order to trap the continuous form material between the cover assembly and the pin assembly. A pin assembly channel in the cover may enclose the pins in the pin assembly to prevent the continuous form material from falling off the pins of the pin assembly during transport.
Alternatively, tractor feeders may accomplish registration of continuous form material by utilizing existing sync marks printed on at least one or more form of the continuous form material. For example, in a 2-up cutter configuration, only one sync mark is required per side as the two sheets are fed and cut together. While for a slit and merge “over-under” dual tractor cutter configuration, for example, a printed sync mark is required on each of the two sheets that are slit and fed separately. During a webbing process, an operator may manually advance the sheet until the sync mark is detected. Cutter controls may be configured to then advance and position a top of a form to a cutter blade by determining a distance of a sync mark to the top of the form. A sync mark “window” may also be defined to so that the cutter control does not falsely detect other print marks as the sync mark.
However, although tractor feeders such as those described above tend to prevent slippage of the continuous form material during a registration process, these tractor feeders are being eliminated and replaced with new “pin-less cutters”. Yet, new pin-less cutters require additional manual registration management, on top of what is required for conventional registration and/or synchronization. For example, a pin-less tractor feeder assembly may require a lead edge detector in a cutter feeder and at least one additional printed sync mark where a distance is known between a lead edge and the sync mark.
Hence, a need exists for systems, methods, and computer readable media for sheet registration in a tractorless sheet processing device using existing sheet features in order to eliminate the need to use printed sync marks for alignment during the automatic initial web loading and cyclic operation of non-tractor pin-less transport and cutter. Notably, the systems, methods, and computer readable media provided herein are able to cooperate with material that does or does not have pin holes, by sensing a specific unique feature already printed on the sheet to use as a sync mark.